FIGURE 1.

The scheme shows the reciprocal interactions between endothelial cells and islet cells. Insulin mediates the production of nitric oxide (NO) through the regulation of the endothelial nitric oxide synthase (eNOS). VEGF-A induces the formation of both new vessels and their fenestrae on the surface of endothelial cells. HGF released from the endothelial maintain both glucose-stimulated insulin release and β-cell mass by inducing their proliferation. ECMs including laminins, collagens and fibronectin produced by the endothelial cells, promotes β-cell growth, maintenance of their differentiation phenotype and ultimately results in higher insulin production.